Section 5 FINAL CONTROL DEVICES

Question 1

62. Refer to Figure 75. What is the flow characteristic determined by the cage?

Answer 1

A. Linear.
B. Cavitation.
C. Quick opening.
D. Equal percentage.

Question 2

63. When replacing a control valve. What is done after opening the bypass valve?

Answer 2

A. Close the upstream and downstream block valves.
B. Close the upstream valve and unbolt the existing valve.
C. Close the downstream block valve and open the upstream block valve.
D. Close the upstream block valve and open the downstream block valve.

Question 3

64. The packing on a valve has been adjusted. At 50% rising signal, the valve opens 40%, and at 50% falling signal, it closes to 60%. How is this corrected?

Answer 3

A. By tightening the packing.
B. By loosening the packing.
C. By replacing the actuator.
D. By replacing the plug and the seat.

Question 4

65. Loop tuning has been performed on a control loop. The valve continues to oscillate. What is the cause?

Answer 4

A. The trim is undersized.
B. The packing is too loose.
C. The trim is oversized.
D. The packing is leaking.

Question 5

66. After cleaning out a tank, the level cannot be controlled when the system is brought back online. What is the cause?

Answer 5

A. The drain valve is obstructed.
B. The drain valve is oversized.
C. The fill valve trim is worn.
D. The fill valve packing is worn.

Question 6

67. What is done when a valve stem has build-up, causing a leak?

Answer 6

A. Replace the O-ring and lubricate the stem.
B. Change the packing size.
C. Clean and polish the stem.
D. Grind and lubricate the stem.

Question 7

68. A valve with a Teflon seat is not providing sufficient shut-off. How is this corrected?

Answer 7

A. By lapping the plug.
B. By lapping the seat.
C. By replacing the seat.
D. By replacing the plug.

Question 8

69. Which actuator is installed on a direct acting wave to make the system fail close?

Answer 8

A. Electric gear.
B. Double-acting air piston.
C. Diaphragm air-to-open.
D. Diaphragm air-to-close.

Question 9

70. What is done when a reverse acting spring and diaphragm actuator does not provide the travel expected?

Answer 9

A. Check the air vent.
B. Lubricate the diaphragm.
C. Move the travel indicator.
D. Decrease the air supply.

Question 10

71. What is done when performing scheduled preventative maintenance on a pneumatic piston actuator?

Answer 10

A. Adjust the travel stop.
B. Adjust the feedback linkage.
C. Replace the O-rings.
D. Replace the diaphragm.

Question 11

72. Refer to Figure 38. When removing a direct-acting spring-opposed valve actuator from the valve bonnet. What is the sequence to disassemble?

Answer 11

A. Relieve spring tension, remove stem connector, then remove yoke locknut.
B. Remove yoke locknut, remove stem connector, then relieve spring tension.
C. Remove stem connector, relieve spring tension, then remove yoke locknut.
D. Remove travel indicator, remove yoke locknut, then remove stem connector.

Question 12

73. What is the procedure for adjusting an electric actuated gate valve after the actuator overhaul and before testing the valve operation?

Answer 12

A. Power off, place valve in mid-position, power on, adjust open limit switch, then adjust close limit switch.
B. Power on, open valve, adjust close limit switch, close valve, then adjust open limit switch.
C. Power on, place valve in mid-position, open valve, adjust open limit switch, close valve, then adjust close limit switch.
D. Power off, open valve, adjust open limit switch, close valve, adjust close limit switch, place valve in mid-position, then power on.

Question 13

74. How is a diaphragm actuator disassembled?

Answer 13

A. By removing the spring tension and removing bolts in a clockwise pattern.
B. By removing bolts in a clockwise pattern and removing the spring tension.
C. By removing the spring tension and removing bolts in a cross pattern.
D. By removing bolts in a cross pattern and removing the spring tension.

Question 14

75. A spring and diaphragm actuator has stopped working. The yoke and the dome are corroded with nitric acid. What is done to correct the problem?

Answer 14

A. Repair the yoke.
B. Replace the cylinder housing.
C. Repair the corroded areas.
D. Replace the actuator.

Question 15

76. Refer to Figure 71. What is the characteristic of the positioner?

Answer 15

A. Linear.
B. Quick opening.
C. Equal percentage.
D. On/off.

Question 16

77. During a preventative maintenance check on a non-spring assisted piston actuator, the following is found during calibration.

Answer 16

• 10% input equals 10% valve travel
• 50% input equals 40% valve travel
• 90% input equals 90% valve travel

What is done?
A.	Align balance beam.
B.	Bench set the valve.
C.	Reduce supply pressure.
D.	Inspect cam orientation.

Question 17

78. What are the steps when a pneumatic positioner is to be removed from service for maintenance?

Answer 17

A. Bypass the valve to maintain appropriate flow, shut off the air supply, then remove the positioner.
B. Bypass the valve to maintain appropriate flow, remove the positioner, then shut off the air supply.
C. Close the valve, depressurize the process line, then remove the positioner.
D. Depressurize the process line, remove the positioner, then shut off the air supply.

Question 18

79. When attempting to calibrate a smart positioner, the hand-held HART communicator fails to communicate with the positioner. What is the cause?

Answer 18

A. Leads are too short.
B. Low circuit noise.
C. Insufficient loop resistance.
D. Shield wire disconnected at one end.

Question 19

80. A valve is stroking properly when air is applied directly to the actuator. When the positioner is connected to the valve, the valve strokes to 100% regardless of input. What is the cause?

Answer 19

A. The feedback arm is misaligned.
B. The nozzle is plugged.
C. The positioner is bypassed.
D. The cam is on backwards.

Question 20

81. After maintenance on a valve, the positioner is reinstalled. Any input signal to the positioner causes the valve to stroke fully and stay there. What is done to correct the problem?

Answer 20

A. Re-attach the feedback linkage.
B. Bench set the actuator.
C. Calibrate the I/P converter.
D. Decrease the supply pressure.

Question 21

82. Refer to Figure 70. What is the procedure to replace the input bellows?

Answer 21

A. Remove tubing, old bellows and flapper assembly, install new bellows, connect tubing, install flapper assembly, then calibrate the positioner.
B. Remove tubing, old bellows and cam, install new bellows, connect tubing, install cam, then calibrate the positioner.
C. Remove tubing and old bellows, align the quadrant beam, install new bellows and connect tubing, then calibrate the positioner.
D. Remove tubing and old bellows, install new bellows and connect tubing, align the quadrant beam, then calibrate the positioner.

Question 22

83. What are the parameters required to configure a VSD?

Answer 22

A. Min-max speeds, fuse size, start method and I/O feedback.
B. Min-max speeds, motor frame size, start method and I/O feedback.
C. Min-max speeds, motor name plate data, start method and I/O feedback.
D. Min-max speeds, ___________________, start method and I/O feedback.

Question 23

84. A variable speed dc drive is connected to a 180-Vdc motor. The 4-20 mA input is 16 mA. What is the armature voltage?

Answer 23

A. 128 V
B. 135 V
C. 144 V
D. 180 V

Question 24

85. A newly-installed conveyor trips when started. The fault code indicates an over current situation. All input signals and supply voltages have been verified. What is the next step to diagnose the problem.

Answer 24

A. Check for shorted leads.
B. Check output shaft for movement.
C. Check __________
D. Check __________